Recent developments in loss of life and evacuation modelling for flood event management in the UK

Abstract

To date the work done in the UK to assess the loss of life and evacuation times for flood risk areas has been limited. To provide the most accurate assessment of loss of life and evacuation times a complex model is required. This paper details the application of a prototype, agent-based Life Safety Model (LSM) to estimate the loss of life in two areas of the Thames Estuary. The LSM models individual receptors (e.g. people and cars) and their dynamic interaction with the floodwater. The LSM estimates deaths from: drowning; exhaustion; building collapse; and vehicles being swept away, as well as evacuation times.The LSM offers a scientifically robust method of assessing residual risk behind flood defences and downstream of dams in terms of fatalities. Importantly, it allows the comparison of different emergency management strategies (e.g. the use of safe havens) that can assist in reducing the loss of life during future floods and dam breaks. The model was validated against historical data from the Canvey Island flood in 1953, during which 58 people lost their lives. The LSM was then applied to the Thamesmead embayment to assess the results for a range of scenarios.

Use of an agent‐based model and Monte Carlo analysis to estimate the effectiveness of emergency management interventions to reduce loss of life during extreme floods

“…The time for the island to be totally inundated would be between 1 and 4 h, dependent on where and how the flood defences failed. This would give occupants sufficient time to relocate upstairs or to move to neighbours with two‐storey premises; however, previous studies (see Di Mauro and Lumbroso, ; Lumbroso and Di Mauro, ) indicate that 12 h is not sufficient for everybody to evacuate the island safely by car and that it would take up to 20 h to evacuate the 38 000 people who currently reside on Canvey Island (Lumbroso et al ., ). This work also made the assumption that the weather conditions were amenable to a mass evacuation, which is often not the case.…”

“…Canvey Island was chosen as a case study because a calibrated two‐dimensional fully hydrodynamic model of the 1953 flood was available (Lumbroso and Di Mauro, ) and details of the failure of the flood defences were available. In 1953 Canvey Island was connected to the mainland by one bridge located in the north‐west of the island (Figure ).…”

“…The LSM can be applied to a range of flood events including fluvial floods, coastal events, dam breaks and floods generated by tsunamis (Lumbroso and Di Mauro, ; Lumbroso et al ., , ). A fundamental philosophical principle driving the development of the LSM was the need to replace as many subjective judgments as possible with a phenomenological approach that provides a transparent basis for making inferences concerning the range of possible outcomes (Johnstone et al ., ).…”

A comparison of the causes, effects and aftermaths of the coastal flooding of England in 1953 and France in 2010

“…The population of the island has risen from an estimated 12 000 in 1953 to over 37 000 today (Baxter, 2005;Lumbroso and Di Mauro, 2008). Access to Canvey Island is currently only possible by two roads both of which are connected to the same roundabout.…”

“…Since 1953 the coastal population on the east coast of England has increased markedly. For example in 1953 the population of Canvey Island was about 12 000 people, today it is in excess of 37 000 (Lumbroso and Di Mauro, 2008). In other areas, the population has increased by between 30 % and 90 % (Baxter et al, 2002).…”